1. Field of the Invention
This invention relates to a shoe insert for use in shoes. More especially, this invention relates to a plastic shoe insert especially for use as a foot bed in shoes. Still more especially, this invention relates to a multi-layered insert for use as a foot bed in shoes, which insert is made of a closed-cell, cross linked polyolefin foam of differing degrees of elasticity, especially through its thickness.
2. Discussion of the Prior Art
It is known that, especially when one is constantly walking on hard floors or paving, severe phenomena of fatigue affect the feet and legs, and can be considered as symptoms of excessive strain. The physical consequences of such strain are by no means negligible, and since there are numerous occupations which are practiced entirely or chiefly on foot, and which are accompanied by a disproportionate frequency of foot ailments, the need has long been felt for an effective and practical preventative remedy therefor.
For the solution of this existing problem, insoles of plastic or of reinforced leather fiber materials have been developed which are precisely fitted anatomically to the foot to be treated. However, their use by persons considered to have healthy feet has proven to be rather unattractive, and their high cost has limited the use of such insoles to cases in which the foot damage caused by stress has already been done. This solution has proven also to be rather unsatisfactory from the purely commercial point of view.
Under normal conditions, the foot performs to a great extent the function of a vibration damper for the unavoidable shocks produced by walking, and it is considerably impaired in this function precisely by the wearing of an insole. Its use is therefore to be equated with interference with the body's own system for vibration damping, and since the shock stress of itself continues to remain the same, overstrain is to be expected to appear in other body members such as the tibia, for example. In addition to the disadvantages of cost and physiological disadvantages, however, there are also obvious esthetic reasons which militate against the more widespread use of such insoles. For example, high-fashion footwear often makes it impossible to use them.